Honestly i'm guessing you always wanted kids? I'm similar situation, i'm 21, i worked but recently went back to college and now only work part time, my partner works and we are jont tenants with my mum in a 3 bedroom with a room to spare ... i am waiting i think until june 2017 but who knows? A lot can change... you should definitely talk. Someone said you both dont work or have a house but i must have missed that post.
Honestly, not everyone aims to be married or own a home, i dont plan on buying a house, we might get married we might not depending on money .. i use my sparemoney to help my family who struggle a lot more than i do financially. If you are both okay with not getting married first, not owning your own home and just being council or renting then i do not see a problem so long as you can provide a roof over a childs head, be selfless and make sacrifices ... there is no perfect time to have kids. I mean people say i shouldnt consider it because i live with my mum... yeah but now im a joint tenant and i have always been one of her main carers so what am i suppose to do? Abandon her to start a family, no she will just be a part of our family. I do not know your situation... i think the first step you have to take is have a talk with your boyfriend, (im not saying you have to be married but make sure he is at least in it for the long haul, and it is a healthy relationship to bring a child into) .. you would need a spare room, i would suggest at least one of you working full time, i dont know your plans after you have kids, i plan on being a SAHM so me working full time first isn't too big of a deal, make sure you ar eboth willing to sacrifice your time to give it to your child, sacrifice a new bag for nappies etc ... try not to worry about other peoples opinions, if you think it is right, it is right for you.
Glad to see someone as young as me waiting